Re: [tech-3d] Digest Number 44

["Don Lopp" <dlopp@xxxxxxxxxxxxxxx>]

Mike- Foregroundverticles cause a problem ewhen they are near the centeral
area  because they become very prominant where as when they are on the
periphery they are not as noticeable and can have a deviation of as much as
2 plus mm but when the verticles are in the centeral area I find that a
deviation of more than 1.5 mm is troubling for me. I have seen so so stereo
pictures of Yosemite which had extreme deviation which added to the stereo
depth but in my opinion did not make for a " good " stereo picture. I
beleive that  poor pictures  are not improved by doing them in stereo- they
are still mediocre pictures with or without stereo. Recently I heard of
shooting stereo with 4x5 cameras which would increase the sharpness but at
the same time would raise the problem of how do you view them-certainly not
in a ortho way unless one is using telephoto lenses which really restricts
the subjects available which  would really restrict me from taking some of
my favorite subjects- I consider 6x7  the perfect option, consistant with a
decent viewer which as of today one must build himself as the commercial
viewers are of mediocre quality as compared with what can be home built.
DON.
----- Original Message -----
From: <tech-3d@xxxxxxxxxxx>
To: <tech-3d@xxxxxxxxxxx>
Sent: Friday, December 08, 2000 3:27 PM
Subject: [tech-3d] Digest Number 44


>
> There are 3 messages in this issue.
>
> Topics in this digest:
>
>       1. Re: Stereo base calculations
>            From: "Michael K. Davis" <zilch0@xxxxxxxxxxxx>
>       2. mars stereo camera request
>            From: John Toeppen <toeppen@xxxxxxxx>
>       3. Re: mars stereo camera request
>            From: Andres Posada O <aposadao@xxxxxxxxxx>
>
>
> ________________________________________________________________________
> ________________________________________________________________________
>
> Message: 1
>    Date: Thu, 07 Dec 2000 23:47:23 -0600
>    From: "Michael K. Davis" <zilch0@xxxxxxxxxxxx>
> Subject: Re: Stereo base calculations
>
>
> Hi Don,
>
> >    Date: Mon, 4 Dec 2000 21:16:06 -0800
> >    From: "Don Lopp" <dlopp@xxxxxxxxxxxxxxx>
> > Subject: Re: Digest Number 41
> >
> > Mike thank you for taking the time to check me out Could you tell me
what
> > the numbers would be for--
>
>
> >75mm lens  for 75 feet to  with a i foot base,
>
> I'll assume you omitted 3000 feet as the far.  The deviation would be
0.98mm.
>
>
>
> > 100mmlens 100 feet to 3000 feet , one foot base
>
> The deviation would be 0.97mm.
>
>
>
> > and finally 135 mm lens - 135 feet to 3000ft with a one foot base ?
>
> The deviation would be 0.96mm.
>
> Interesting!  I realize now, that in my last response to you, when I was
> comparing the percent of MAOFD produced by each of these combinations, I
> had incorrectly concluded that your OFD shrinks a lot as you increase
focal
> length, but it's really very close to being constant - at right under
1mm -
> which is exactly what you had said originally!  I have to hand it to you
> for really knowing what your method is producing on film.
>
> Summarizing:
>
> 39.1 % of MAOFD for a  75mm lens = 0.98mm OFD when Near =  75 feet, Far =
3000
> 29.1 % of MAOFD for a 100mm lens = 0.97mm OFD when Near = 100 feet, Far =
3000
> 21.3 % of MAOFD for a 135mm lens = 0.96mm OFD when Near = 135 feet, Far =
> 3000
>
>
> > I realize that my symplistic plan would be worthless for close in stereo
> > such as when they tried to shoot stereo of tSports Illustrated models
last
> > summer although common sense should have indicated  that itcould not be
> done
> > the way they attempted to do it allthough your system woul have
indicated
> > whether there was a way they could do it . They were partially saved by
> > having some RBT 35mm cameras available though in my opinion the show
> > presented in Phoenix was , in my opinion,one of the lousiest 3D shows I
> have
> > ever seen at a NSA convention ( I am referring to the technical aspects
of
> > the program -mostly too hyper). You are correct in assuming that I fine
> tune
> > my stereo base numbers based on previous experience such as any
foreground
> > verticles or lack of foreground verticles or when verticles are only on
> > outer edges not in center( I believe that central verticles are not
> usefull
> > in my pictures- though not allways possible to avoid). A
>
> How exactly to you respond to the presence of foreground verticles?  Do
you
> reduce base or increase it?   Can you explain why you handle the presence
> of foreground verticles differently?  Is it just aesthetics?
>
> Thanks!
>
> Mike Davis
>
>
>
>
> ________________________________________________________________________
> ________________________________________________________________________
>
> Message: 2
>    Date: Thu, 07 Dec 2000 22:30:59 -0800
>    From: John Toeppen <toeppen@xxxxxxxx>
> Subject: mars stereo camera request
>
> Included is an email I received requesting information -- if anyone can
> help this person, please respond to him (and to Tech3D) directly at:
>
>   Piotr Moskal piotr.moskal@xxxxxxxx
>
> Hello,
>
> ... I need a stereoscopic camera head that could be used in a
> terrain recognition system onboard an experimental Mars rover (maybe
> something similar to AH64 set?). Do you know any companies that are
> selling such equipment? Could you at least guide me to any site where I
> could figure
> out how to buy / order such equipment? Thanks in advance.
>
>
> best regards,
> Piotr Moskal
> "
>
> [Non-text portions of this message have been removed]
>
>
>
> ________________________________________________________________________
> ________________________________________________________________________
>
> Message: 3
>    Date: Fri, 08 Dec 2000 09:13:28 -0500
>    From: Andres Posada O <aposadao@xxxxxxxxxx>
> Subject: Re: mars stereo camera request
>
> Yes. Contact Carl Tung at VREX, vrex.com, phone 914-345-8877. Please say
> I sent you. He has several alternatives for your exact needs.
> Andres Posada
>
> John Toeppen wrote:
> >
> > Included is an email I received requesting information -- if anyone can
> > help this person, please respond to him (and to Tech3D) directly at:
> >
> >   Piotr Moskal piotr.moskal@xxxxxxxx
> >
> > Hello,
> >
> > ... I need a stereoscopic camera head that could be used in a
> > terrain recognition system onboard an experimental Mars rover (maybe
> > something similar to AH64 set?). Do you know any companies that are
> > selling such equipment? Could you at least guide me to any site where I
> > could figure
> > out how to buy / order such equipment? Thanks in advance.
> >
> > best regards,
> > Piotr Moskal
> > "
> >
> > [Non-text portions of this message have been removed]
> >
>
>
> ________________________________________________________________________
> ________________________________________________________________________
>
>
>
>


-------------------------- eGroups Sponsor -------------------------~-~>
eGroups eLerts
It's Easy. It's Fun. Best of All, it's Free!
http://click.egroups.com/1/9698/1/_/520353/_/976394862/
---------------------------------------------------------------------_->